Cardanol blocked isocyanate adhesion promotor for PVC plastisol

Abstract

The present invention relates to a PVC plastisol composition comprising at least one vinyl chloride polymer selected from polyvinylchlorides and copolymers of vinyl chloride with one or more monomers; at least one plasticizer; at least one epoxy resin; and at least one isocyanate resin blocked with cardanol. The PVC plastisol composition of this invention provides strong adhesion to the surface of various metals or various undercoats of metals by thermal treatment for a short time at 100° C.-200° C. and is excellent in storage stability. In addition, it offers good rheological properties with improved yield value dosing and viscosity stability during applications compared to the nonylphenol blocked isocyanate PVC adhesion promotor.

The invention claimed is: 
     
       1. A plastisol composition comprising
 (a) at least one vinyl chloride polymer selected from the group consisting of polyvinylchlorides and copolymers of vinyl chloride with one or more monomers; 
 (b) at least one plasticizer; 
 (c) at least one epoxy resin; and 
 (d) at least one isocyanate resin blocked with cardanol. 
 
     
     
       2. The plastisol composition of  claim 1 , wherein the at least one isocyanate resin is a polyisocyanate resin, polyisocyanate polymer resin, urethane prepolymer of polyisocyanate resin, or a mixture thereof. 
     
     
       3. The plastisol composition of  claim 2 , wherein the polyisocyanate resin is a diisocyanate represented by the general formula: 
       
         
           
           
               
               
           
         
       
       wherein A is a benzene or naphthalene ring; NCO is an isocyanate group; Z is a halogen atom or alkyl or alkoxyl group having at most 3 carbon atoms and n is 0, 1 or 2. 
     
     
       4. The plastisol composition of  claim 3 , wherein the diisocyanate is selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,4-naphthylene diisocyanate, 1,5-naphthylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and 1-isopropylbenzene 2,4-diisocyanate. 
     
     
       5. The plastisol composition of  claim 2 , wherein the polyisocyanate resin is a diisocyanate represented by the general formula: 
       
         
           
           
               
               
           
         
       
       wherein B is a benzene or naphthalene ring; (CH 2 )m NCO is an alkylene isocyanate group; Z is a halogen atom or alkyl or alkoxy group having at most 3 carbon atoms; m is 1 or 2 and n is 1 or 2. 
     
     
       6. The plastisol composition of  claim 5 , wherein the diisocyanate is selected from the group consisting of ω,ω′-diisocyanate-1,2-dimethylbenzene, and ω,ω′-diisocyanate-1,3-dimethylbenzene. 
     
     
       7. The plastisol composition of  claim 2 , wherein the polyisocyanate resin is a diisocyanate represented by the general formula: 
       
         
           
           
               
               
           
         
       
       wherein A is an alkylene group having at least 3 carbon atoms; D is a benzene or naphthalene ring; Z is a halogen atom or alkyl or alkoxy group having at most 3 carbon atoms and n is 0, 1 or 2. 
     
     
       8. The plastisol composition of  claim 7 , wherein the diisocyanate is selected from the group consisting of 4,4′-diphenylmethane diisocyanate, 2,2′-dimethyldiphenylmethane 4,4′-diisocyanate, diphenyldimethylmethane 4,4′-diisocyanate, and 3,3′-dichlorodiphenyldimethylmethane 4,4′-diisocyanate. 
     
     
       9. The plastisol composition of  claim 2 , wherein the polyisocyanate resin is a diisocyanate represented by the general formula: 
       
         
           
           
               
               
           
         
       
       wherein Z is a halogen atom or alkyl or alkoxy group having at most 3 carbon atoms; m is 0 or 1 and n is 0, 1 or 2. 
     
     
       10. The plastisol composition of  claim 9 , wherein the diisocyanate is selected from the group consisting of biphenyl 2,4′-diisocyanate, biphenyl 4,4′-diisocyanate, 3,3′-di methyl biphenyl 4,4′-diisocyanate, and 3,3′-dimethoxybiphenyl 4,4′-diisocyanate. 
     
     
       11. The plastisol composition of  claim 1 , wherein the at least one plasticizer is selected from the group consisting of phthalates, mixed alkyl phthalates, adipates, sebacates, phosphates, trimellitates, and combinations thereof. 
     
     
       12. The plastisol composition of  claim 1 , wherein the at least one epoxy resin is selected from the group consisting of aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, glycidyl ester resin, thioglycidyl ether resin, N-glycidyl ether resin, and combinations thereof. 
     
     
       13. The plastisol composition of  claim 12 , wherein the at least one epoxy resin comprises a glycidyl ether of polyhydric phenol. 
     
     
       14. The plastisol composition of  claim 12 , wherein the at least one epoxy resin comprises at least one glycidyl ether selected from the group of glycidyl ethers of: resorcinol, hydroquinone, bis-(4-hydroxy-3,5-difluorophenyl)-methane, 1,1-bis-(4-hydroxyphenyl)-ethane, 2,2-bis-(4-hydroxy-3-methylphenyl)-propane, 2,2-bis-(4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis-(4-hydroxyphenyl)-propane, bis-(4-hydroxyphenyl)-methane, novolac resins, and combinations thereof. 
     
     
       15. The plastisol composition of  claim 12 , wherein the at least one epoxy resin comprises at least one dihydric phenol of the following structure: 
       
         
           
           
               
               
           
         
       
       wherein R′ is a divalent hydrocarbon radical of a dihydric phenol, and p is an average value between 0 and about 7. 
     
     
       16. The plastisol composition of  claim 12 , wherein the at least one epoxy resin comprises at least one multifunctional epoxy resin selected from the group consisting of the diglycidyl ether of bisphenol-A, derivative of diglycidyl ether of bisphenol-A,-and diglycidyl ether of bisphenol-F. 
     
     
       17. The plastisol composition of  claim 16 , wherein the at least one epoxy resin comprises at least one multifunctional epoxy resin of the following structure: 
       
         
           
           
               
               
           
         
       
       wherein R″ is H or CH 3 , and p is an average value between 0 and about 7. 
     
     
       18. The plastisol composition of  claim 1 , wherein the amount of cardanol is 1 to 2 times by molar equivalent the isocyanate resin.